MongoDB and Python interactive

Drive module

• pymongo is a common operation in the python drive module MongoDB
• Available to download and install pip

 pip install pymongo

Create a connection

• MongoClient is MongoDB client proxy object can be used to perform CRUD operations, but also built connection pool

 from pymongo import MongoClient
 client = MongoClient(host="localhost",port=27017)
 client.admin.authenticate("admin","123456")

Data is written

• insert_one insert_many two functions and data can be written to MongoDB

 client.school.student.insert_one({"name":"alex"})

 client.school.student.insert_many({"name":"bob"},{"name":"cindy"})

data query

• find_one and find two functions can be found in the data from MmongDB

 student = client.school.student.find_one({"name":"alex"})
 print(student)

 students = client.school.student.find({})
 for one in students:
    print(one["_id"],one["name"])

• skip: query for data classification
• limit: for data paging query

 students = client.school.student.find({}).skip(0).limit(10)

• count_documents: query total number of records

 count = client.school.student.count_documents({})

• distinct: the query does not duplicate field

 students = client.school.student.distinct("name")

• sort: sorting query results

 students = client.school.student.find().sort([("name",-1)])

Data Modification

• update_one update_many two functions and can modify the data MongoDB

 client.school.student.update_one({"name":"alex"},{"$set":{"sex":"女"}})

 client.school.student.update_many({},{"$set":{"grade":"七年级"}})

Data deletion

• delete_one and delete_many two functions can be deleted MongoDB data

 client.school.student.delete_one({"name":"alex"})

 client.school.student.delete_many({})

File storage

Connection GridFS

• GridFS MongoDB is a document storage solutions, primarily for storing more than 16M documents

from gridfs import GridFS
db = client.school
gfs = GridFS(db,collection="book")

save document

• put function can save the file to the GridFS

file = open("D:/Python编程：从入门到实践.pdf","rb")
args = {"type":"PDF","keyword":"Python"}
gfs.put(file,file="Python编程：从入门到实践.PDF",**args)
file.close()

Find Files

• find_one and find function can find files stored GridFS

book = gfs.find_one({"filename":"Python编程：从入门到实践.PDF"})
print(book.keywode)

books = gfs.find({"type":"PDF"})
for one in books:
   print(one.filename）

To determine whether the file is stored

• exists can determine whether a file is stored GridFS

rs = gfs.exists({"filename":"Python编程：从入门到实践.PDF"})
print(rs)

Read the file

• The get function can read files from GfridFS, and can only be read by the primary key

from bson.objectid import ObjectId
book = gfs.find_one({"filename":"Python编程：从入门到实践.PDF"})
id = book._id
document = gfs.get(ObjectId(id))
file = open("D:/Python从入门到实践.PDF","wb")
file.write(document.read())
file.close()

Delete Files

• delect function can delete files from GridFS, the same can only remove (the primary key to find the file) by the primary key

from bson.objectid import ObjectId
book = gfs.find_one({"filename":"Python编程：从入门到实践.PDF"})
id = book._id
gfs.delete(ObjectId(id))